1. Field of the Invention
This invention relates to a video endoscope of the kind having a semiconductor image converter which is incorporated in the endoscope and which receives the image of the object illuminated periodically by an illumination device with a sequence of partial colors and converts the same into video signal components which correspond to partial color separations of the image, and which are written, successively and selectively separated according to partial colors, in an intermediate store and then read out simultaneously for the formation of a real-time individual image, and are processed for the representation of the individual image with a video processor into television-compatible video signals.
2. Description of the Prior Art
Modern endoscopes are semiconductor image converters to generate image signals. These generate, from the light falling onto their sensors (the light is usually conducted through a photoconductor to the endoscope) signals which correspond to the object that is to be inspected. These signals are, for the generation of video-compatible signals, subjected to a further processing and finally reproduced on a television monitor. To generate color pictures with such endoscopes it is known, for example, from DE-PS 34 35 598 to illuminate the object successively with the three primary colors, to store intermediately the respective color separations and then to read out simultaneously the three color separations in the next half image period or image period and compose the same into a television-compatible signal.
One problem with the use of such an endoscope consists in that, for objects having a different degree of reflection and/or at a different distance, the amount of light falling onto the image converter can lead to an overradiation or saturation of the image converter, or is no longer sufficient to generate a good television picture if it is too slight.
The endoscope arrangement disclosed in DE-PS 34 32 018 proposes for solving this problem, an automatic brightness regulation system working in a purely electronic manner, through the regulation of the voltage, applied to the light source emitting the light as a function of the result of the integration of the processed RGB-signals by the semiconductor image converter. However, it has been shown that electronic regulation alone does not achieve the high dynamic of the light intensity necessary for a good illumination of the object, to be inspected, at various object distances.